Ajaxify Your Zend_Form Validation with jQuery

Jon Lebensold posts an update to his excellent screencast; We’re going to take what was put together in the last 3 videos and now include some server-side validation that will appear asynchronously. This is an example of using Zend_Form as a validation tool via JSON.

UPDATE: as a couple people have mentioned, you can cut down your IndexController even more by using the Zend_Json view helper:
public function validateformAction()
{
$f = new Form_Registration();
$f->isValid($this->_getAllParams());
$this->_helper->json($f->getMessages());
}